Shower advice please

[xAlex]

Hi All,

Can you give me advice on this: Project: shower replacement.

New Shower: Trident II
Q1 - Power rating says 7.8 to 8.5kW - why is there a range?
Q2 - Can anyone identify the cable size from the diameter of the sheath? - half inch approx (see photo)
Q3 - Current shower is connected to a 32A MCB on the non-RCD side. All ways on the RCD side are and cabel would not reach anyway. What is the best way to resolve this? (32A furthest right on pic)

Thank you all.

Untitled

• xAlex
• 8 Jul 2009
• 1

Untitled

• xAlex
• 8 Jul 2009
• 1

Untitled

• xAlex
• 8 Jul 2009
• 1

 

[securespark]

The element is most probably 7.8kW @ 230V and 8.5kW @ 240V.

Looks like 6mm².

Fit a stand-alone 30mA RCD & enclosure.

 

[Spark123]

7.8kw@230v
8.5kw@240v
Either way you need a 40A circuit.
Not 100% sure on the size of the cable, is the earth stranded? I'd guess around 6mm but it could be 4mm.
Easiest solution eventually would be to change the MCB to an RCBO, but not until it has been verified that the cable is sufficient for the load.
Upgrading the shower circuit is notifiable to your LABC under part p.

 

[securespark]

Might as well say this is notifiable.

You should really uprate the MCB too, but then you should check the cable is up to it.

 

[securespark]

Doh and double Doh.

 

[xAlex]

OK, thanks,

So - use a stand-alone RCD - 40A+, connected to a 40A MCB.
Cable-run is only short through non-insulating material <5m. So, if it's 6mm, should be OK.

...what is the d'oh refernce?

 

[securespark]

Just a reference to 123 posting the same as me & then me posting stuff after that he already included in his post....

As 123 says, you could use an RCBO instead.

Is the shower cable trunked?

 

[xAlex]

LOL - oh.

NO - the cupboard containing the CU is directly below the bathroom. Th CU is at ceiling height in the cupboard. Cable goes up into floor then is plastered into wall in airing cupbord and makes a 6-inch apearance before going through wall into shower. No markings are visable unfortunately.
thanx

 

[xAlex]

Just a reference to 123 posting the same as me & then me posting stuff after that he already included in his post....

As 123 says, you could use an RCBO instead.

Is the shower cable trunked?

Would an RCBO kbe available for this CU do you think?

 

[securespark]

Yes. Or you can fit a stand-alone RCD. As you say, it should be rated at least to the MCB and be 30mA.

Is there an isolation switch for the shower? This should be uprated if necessary.

 

[Spark123]

I think you can get the pods for those MCBs to make them into an RCBO, however if you're buying a 40A one anyway you may as well get it ready assembled.

 

[xAlex]

Thank you.

Ref the cable size - i guess I can go measure the 6mm at Wicks - see if it's the same?

 

[ColJack]

almost certainly 6mm² as it's 13.5mm across.. as it says in the WIKI //www.diynot.com/wiki/electrics:flatpvccables

it's definitely not 17mm across so it's not 10mm².

 

[Goldberg]

Given the frequency of the forum question "which cable have I got", and the same question arising in dark cupboards and lofts, and the fact that there's a special entry in the Wiki to answer the question, isn't it wonderful that all T&E sheaths are the same shade of grey?

Should the industry go one step further, and make the insulation colour for ALL conductors the same colour - perhaps, um, grey?

 

[RF Lighting]

Given the frequency of the forum question "which cable have I got", and the same question arising in dark cupboards and lofts, and the fact that there's a special entry in the Wiki to answer the question, isn't it wonderful that all T&E sheaths are the same shade of grey?

Should the industry go one step further, and make the insulation colour for ALL conductors the same colour - perhaps, um, grey?

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